Angela Rayner has revealed how she borrowed £5,600 so she could have a "boob job" on her 30th birthday.
Labour's deputy leader said she underwent the cosmetic surgery after losing weight.
"I had my boob job on my 30th birthday," she told the Financial Times.
"I'd lost six stone thanks to my personal trainer, but my boobs just looked like two boiled eggs in socks.
"You know, like basset hound ears. You can't be 30 and have a chest like an 84-year-old granny.
"I had spent about 14 months losing my baby weight. I was 17 stone after I had my children."
The 42-year-old Mancunian has three children - the first being born when she was 16.
And in November 2017 she became a grandmother.
Ms Rayner spoke to the newspaper as part of a wide-ranging interview in which she also discussed the party's chances at the next election.
Recent polls give Labour a healthy lead over the Conservatives, but she insisted the leadership is aware it needs to build back trust with the electorate.
"We've changed. People are willing to listen," she said.
"But the idea that people are running out of their doors saying, 'yay, Labour' is not where they are.
"They don't want us to get ahead of ourselves."